import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * @author 兴趣使然黄小黄
 * @version 1.0
 * @date 2023/3/16 20:52
 * 用于数据库连接和关闭资源
 */
@SuppressWarnings({"all"})
public class DBUtil {
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/jdbc_test?characterEncoding=utf8&useSSL=false";
    private static final String USER_NAME = "root";
    private static final String PASSWORD = "123456";

    private volatile static DataSource dataSource = null;

    private static DataSource getDataSource(){
        if (dataSource == null) {
            synchronized (DBUtil.class) {
                if (dataSource == null) {
                    dataSource = new MysqlDataSource();
                    ((MysqlDataSource) dataSource).setURL(URL);
                    ((MysqlDataSource) dataSource).setUser(USER_NAME);
                    ((MysqlDataSource) dataSource).setPassword(PASSWORD);
                }
            }
        }
        return dataSource;
    }

    // 获取连接
    public static Connection getConnection() throws SQLException {
        return getDataSource().getConnection();
    }

    // 关闭连接
    public static void close(Connection connection, PreparedStatement statement, ResultSet resultSet){
        if (resultSet != null){
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (statement != null){
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (connection != null){
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
